The field of the invention relates to systems and methods for data processing and more particularly to systems and methods that employ facial recognition to manage databases containing images of individuals.
Computerized databases can be adapted to store many different kinds of data, including sounds, images and text. This flexibility allows database designers to construct databases that have data records that organize and store information in several different formats, such as text and sound and thereby to provide database systems that are more particularly suited to the application at hand.
In one common example, government agencies and businesses use computer databases to store information about select individuals into data records that include demographic data stored as text information and a picture of the individual stored as a digitally encoded image. Therefore, a State Department of Motor Vehicles, can create a database of registered drivers that includes a data record for each registered driver. Each data record can store text information, such as the driver""s name and address, and image information, such as a digitally encoded picture of the driver. The Department of Motor Vehicles can maintain this record, and continually update the contents as the driver""s history and data change.
Although computer databases provide an efficient way to store image and text data, they generally fail to provide any way to search or sort the image information stored therein. This inability is particularly burdensome if the image information is the most reliable or complete information in the data record.
Moreover, this inability prevents an operator from automatically searching through the database to find a particular image of a person. Accordingly, to search the images in a database, the operator must call up each data record and view that record""s stored image. This is such a time consuming and labor intensive process, that image searches of large databases is practically impossible. Consequently, there is little to prevent a person from registering multiple times with an agency, such as the Registry of Motor Vehicles, or a State Welfare Department, by providing fraudulent demographic data during each registration.
Moreover, the quality and characteristics of the images stored in the database can vary widely. For example, the grey scale of any two images can be markedly different. These variations make it more difficult for an operator to compare stored images.
Therefore it is an object of the present invention to provide improved systems and methods for maintaining databases that store image information as part of a data record.
It is a further object of the present invention to provide systems and methods that can efficiently employ image information to control the entry of data into a database.
It is yet another object of the invention to provide improved systems and methods for storing image information in a normalized format within a database.
These and other objects of the present invention will become apparent by following the description of certain embodiments of the present invention.
The present invention provides systems and methods that employ facial recognition to create, maintain and use databases that store data records of individuals. In particular, the present invention provides systems and methods that are adapted to employ select facial recognition techniques to analyze a picture of a person""s face. These select facial recognition techniques generate a set of values, hereinafter referred to as a xe2x80x9cprojection signalxe2x80x9d, that, as a set, are descriptive of the analyzed picture image and provide for highly compact storage of the critical identity characteristics of a person""s face. The generated projection signal can be stored as a data field in a data record that is associated with the individual depicted in the picture. This data record can also include demographic data fields for organizing information, such as address information, social security numbers, and other identifying information with the image information. The invention provides systems and methods that are adapted to work with data records that include data fields of descriptive image information, and to provide systems that can search, compare and sort data records according to image information recorded therein.
To this end, systems and methods are described for creating and employing databases that have data records which contain image information of a person""s face. These database systems and methods are adapted for efficiently storing, sorting, and comparing data records as a function of the image of a person""s face.
In one embodiment of the invention, systems are provided for manufacturing identification cards, such as driver""s licenses, military identification cards, welfare identification cards, pistol permits and other photo-identification cards. The systems are adapted for performing a select principal component analysis facial recognition technique. The facial recognition technique employed by the present invention allows, in one use, the systems to police the manufacture of identification cards to eliminate issuing multiple cards under different names to a single applicant.
These systems generally include an image acquisition element, such as a video camera or a photographic camera and a scanner, that generates a digitized picture of the applicant""s face. A vector memory stores a plurality of eigenvectors defining a multi-dimensional image space. A data processor, such as a conventional workstation, is configured to project the digitized picture onto the multi-dimensional image space, to encode the picture as a weighted function of the plural eigenvectors. An image database couples to the data processor to provide storage for a database of known projection signals each being representative of a weighted set of the eigenvectors associated with an image of a specific person""s face. A demographic database stores a number of data records wherein each data record is associated with a respective one of the stored projection signals and the individual whose image is represented thereby. Each data record also includes an identification signal for identifying that particular data record.
Typically, the data processor includes a recognition program element that is adapted for recognizing a person. Generally, the recognition program element compares the generated projection signal against the projection signals stored in the system. As the projection signals represent the image of a person""s face, similar projection signals are likely to represent the same person or a person with a similar appearance. Therefore, the program element is adapted to determine whether the generated projection signal is substantially representative of one or more of the stored projection signals and to indicate if a match is detected.
In a further embodiment, the recognition program element includes a text query element for comparing text information with the identification signals stored in the data records. The text query element compares, sorts and orders data records as a function of text signals, such as demographic data, stored in the data records. In an optional configuration, the recognition program element employs the text query element to identify a subset of data records as a function of select demographic data. In a subsequent operation, the recognition program element operates on the subset of data records to determine whether the generated projection signal is substantially representative of one of the stored projection signals.
In a preferred embodiment of the present invention, these systems include a location device that searches through the acquired picture to identify a portion of the picture that contains an image of a person""s face. For example, in a picture that depicts a person standing in front of a wall in a police line up, the location device will ignore the background wall and other clutter and will identify that portion of the picture that contains the image of the person""s face. In one embodiment, the location device has a prefilter element that makes a preliminary examination of one portion of the picture to determine if that portion of the picture is likely to contain the image of a person""s face. One type of prefilter element has a grey-scale variance detector that determines how much variance exists between the grey-scale of the selected picture portion, and the typical grey-scale of a picture portion that contains a face. This computationally efficient calculation allows the prefilter element to distinguish quickly between a portion of the picture that depicts a wall or a screen positioned behind the person, and a portion of the picture that contains the image of the person""s face.
Preferably the recognition program element also includes a normalizing element that adjusts the acquired picture according to preselected user criterion. The normalizing element typically includes an element for selectively adjusting a grey-scale parameter of the acquired picture, and an element for selectively adjusting an inclination or tilt parameter of the picture. This normalization element helps minimize problems during the recognition process which are caused by variations in conditions, such as lighting, during image acquisition.
In one embodiment, an enforcement mechanism monitors the recognition program and notes if any matches occur between the generated projection signal and the stored projection signals. The enforcement mechanism notes each favorable comparison and makes a list of every data record that appears to contain an image of the person applying for an identification card. The enforcement mechanism may further include an image server element that is adapted for storing pictures associated with respective ones of said data records. A monitor coupled to the image server displays the pictures of those people that have similar image characteristic as the applicants. An operator can detect if the Applicant is attempting to register into the database under a different name.
In another option, a printer element can connect to the system and record information representative of the picture signal and the identification signal onto a blank data card to generate an identification card. In one embodiment, the enforcement mechanism couples to the printer and prevents the printer from printing an identification card for any data record associated with a picture that is substantially similar to the picture of the applicant.
In a further embodiment of the present invention, the identification card manufacturing system also includes a selection element that selects a portion of the picture that represents a select characteristic of the applicant""s face. In one example, the selection element selects the portion of the picture that represents the applicant""s eyes. By analyzing one portion of a person""s face, the system can recognize a person that is wearing a disguise, such as a beard or wig. In this example, the system projects the portion of the picture that includes the image of the person""s eyes onto the multi-dimensional space, and generates a set of values that are descriptive of this portion of the picture. The recognition program element compares the generated values against values stored in the database and identifies data records having images similar to the applicant""s image.
In another embodiment of the present invention, systems are provided for sorting pictures stored with data records. In particular, systems are described that sort pictures as a function of the class of object, such as whether the image can be classified as a face, an eye, or a mouth. These sorting systems are adapted for sorting through a database of pictures to identify those pictures that represent a select class of objects. In one particular example, the sorting system is adapted to sort through a database of pictures to identify those pictures that represent the face of a person. The system can then make a list of the data records that fail to contain an image of a face, and a system operator can examine these records to identify those records that are to be deleted from the system.
Generally these systems include a picture memory adapted for storing picture signals, a reference memory having storage for the plural eigenvectors of a multi-dimensional image space and having storage for a subspace signal representative of a subspace defined by the plural eigenvectors, a selection element for selecting a picture signal from the picture memory and for generating a projection signal representative of the picture signal encoded as a weighted function of the plural eigenvector signals, a computing element for computing a distance signal that represents the distance between a point defined by the projection signal and the space defined by the subspace signal, and a classification element for determining as a function of the distance signal whether a picture signal is representative of an image of a person. This system therefore provides a mechanism to search through a database of images and identify those data records that contain image data of a particular class of objects, such as faces.
In one embodiment, these systems include an element for deleting automatically a picture signal from the picture memory as a function of the distance signal. Optionally, the system includes a demographic database memory for storing data records, and an element for deleting a data record from the demographic database as a function of the generated distance signal.
The invention will now be explained with reference to certain illustrated embodiments to provide greater detail of the structure and operation of the systems and methods that can be realized by the present invention.